The protected pentasaccharide (I) was converted to the corresponding thioglycoside by epoxidation with dimethyldioxirane followed by epoxide opening with ethanethiol in the presence of trifluoroacetic acid. Subsequent acylation of the free hydroxyl group with benzoyl chloride afforded the thioglycoside benzoate (II). Alternatively, treatment of (I) with dimethyldioxirane in the presence of 4-penten-1-ol and ZnCl2 and subsequent O-benzoylation furnished the pentenyl benzoate (III). Condensation of either the thioethyl donor (II) or the pentenyl donor (III) with the protected serine glycoside acceptor (IV) using N-iodosuccinimide and triflic acid afforded the coupled product (V).

Desilylation of (V) with tetrabutylammonium fluoride followed by acetylation of the free hydroxyl groups provided the fully acylated compound (VI). Reductive acetylation of the azido group of (VI) using a 1:1 mixture of thioacetic acid and pyridine gave rise to the acetamide (VII). The benzyl ester of (VII) was then cleaved by hydrogenolysis over Pd/C to yield the carboxylic acid (VIII).

Coupling of the protected serine O-hexasaccharide (VIII) with the tetrapeptide ester Ala-Val-Ala-Val-OBn (A) by means of HATU afforded the Fmoc-pentapeptide O-hexasaccharide (IX). The Fmoc group of (IX) was then deprotected by treatment with morpholine, and the deprotected amine was coupled with a second unit of Fmoc-Ser(O-hexasaccharide) (VIII) to produce adduct (X).

A further deprotection and coupling cycle of (X) with the serine derivative (VIII) furnished (XI).

The Fmoc protecting group of (XI) was removed by means of morpholine and the resulting amine was acylated with Ac2O to give acetamide (XII).

Hydrogenolysis of the benzyl ester group of (XII) and subsequent hydrazinolysis of the acetate and benzoate esters afforded the fully deprotected product, which was finally coupled with tripalmitoyl S-glyceryl-Cys-Ser-N-(3-aminopropyl)amide (XIII) to furnish the title compound.

The protected pentasaccharide (I) was converted to the corresponding thioglycoside by epoxidation with dimethyldioxirane followed by epoxide opening with ethanethiol in the presence of trifluoroacetic acid. Subsequent acylation of the free hydroxyl group with benzoyl chloride afforded the thioglycoside benzoate (II). Alternatively, treatment of (I) with dimethyldioxirane in the presence of 4-penten-1-ol and ZnCl2 and subsequent O-benzoylation furnished the pentenyl benzoate (III). Condensation of either the thioethyl donor (II) or the pentenyl donor (III) with the protected serine glycoside acceptor (IV) using N-iodosuccinimide and triflic acid afforded the coupled product (V).

Desilylation of (V) with tetrabutylammonium fluoride followed by acetylation of the free hydroxyl groups provided the fully acylated compound (VI). Reductive acetylation of the azido group of (VI) using a 1:1 mixture of thioacetic acid and pyridine gave rise to the acetamide (VII). The benzyl ester of (VII) was then cleaved by hydrogenolysis over Pd/C to yield the carboxylic acid (VIII).

Coupling of the protected serine O-hexasaccharide (VIII) with the tetrapeptide ester Ala-Val-Ala-Val-OBn (A) by means of HATU afforded the Fmoc-pentapeptide O-hexasaccharide (IX). The Fmoc group of (IX) was then deprotected by treatment with morpholine, and the deprotected amine was coupled with a second unit of Fmoc-Ser(O-hexasaccharide) (VIII) to produce adduct (X).

A further deprotection and coupling cycle of (X) with the serine derivative (VIII) furnished (XI).

The Fmoc protecting group of (XI) was removed by means of morpholine and the resulting amine was acylated with Ac2O to give acetamide (XII).

Hydrogenolysis of the benzyl ester group of (XII) and subsequent hydrazinolysis of the acetate and benzoate esters afforded the fully deprotected product, which was finally coupled with tripalmitoyl S-glyceryl-Cys-Ser-N-(3-aminopropyl)amide (XIII) to furnish the title compound.

The protected pentasaccharide (I) was converted to the corresponding thioglycoside by epoxidation with dimethyldioxirane followed by epoxide opening with ethanethiol in the presence of trifluoroacetic acid. Subsequent acylation of the free hydroxyl group with benzoyl chloride afforded the thioglycoside benzoate (II). Alternatively, treatment of (I) with dimethyldioxirane in the presence of 4-penten-1-ol and ZnCl2 and subsequent O-benzoylation furnished the pentenyl benzoate (III). Condensation of either the thioethyl donor (II) or the pentenyl donor (III) with the protected serine glycoside acceptor (IV) using N-iodosuccinimide and triflic acid afforded the coupled product (V).

Desilylation of (V) with tetrabutylammonium fluoride followed by acetylation of the free hydroxyl groups provided the fully acylated compound (VI). Reductive acetylation of the azido group of (VI) using a 1:1 mixture of thioacetic acid and pyridine gave rise to the acetamide (VII). The benzyl ester of (VII) was then cleaved by hydrogenolysis over Pd/C to yield the carboxylic acid (VIII).

Coupling of the protected serine O-hexasaccharide (VIII) with the tetrapeptide ester Ala-Val-Ala-Val-OBn (A) by means of HATU afforded the Fmoc-pentapeptide O-hexasaccharide (IX). The Fmoc group of (IX) was then deprotected by treatment with morpholine, and the deprotected amine was coupled with a second unit of Fmoc-Ser(O-hexasaccharide) (VIII) to produce adduct (X).

A further deprotection and coupling cycle of (X) with the serine derivative (VIII) furnished (XI).

The Fmoc protecting group of (XI) was removed by means of morpholine and the resulting amine was acylated with Ac2O to give acetamide (XII).

Hydrogenolysis of the benzyl ester group of (XII) and subsequent hydrazinolysis of the acetate and benzoate esters afforded the fully deprotected product, which was finally coupled with tripalmitoyl S-glyceryl-Cys-Ser-N-(3-aminopropyl)amide (XIII) to furnish the title compound.